Reversible and selective antagonism by suramin of ATP-activated inward current in PC12 phaeochromocytoma cells.
1. The effects of suramin on an adenosine 5'-triphosphate (ATP)-activated inward current were investigated in PC12 phaeochromocytoma cells with whole-cell voltage-clamp techniques. 2. Suramin (30 to 300 microM) inhibited the ATP-activated current in a dose-dependent manner. The inhibitory effects were reversible and competitive. 3. Suramin also suppressed the current activated by adenosine 5'-O-(3-thiotriphosphate) but did not affect the current activated by nicotine. Suramin did not affect the suppression of a K current induced by methacholine. 4. The results suggest that suramin antagonizes the ATP-receptor-operated membrane current reversibly and selectively.
Nakazawa
K
K
Division of Pharmacology, National Institute of Hygienic Sciences, Tokyo, Japan.
Fujimori
K
K
Takanaka
A
A
Inoue
K
K
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology; D000310:Adrenal Gland Neoplasms / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D008688:Methacholine Compounds / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D010673:Pheochromocytoma / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects; D013498:Suramin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D008688:Methacholine Compounds; D015221:Potassium Channels; C022571:adenosine 5'-O-(3-thiotriphosphate); D013498:Suramin; D009538:Nicotine; D000255:Adenosine Triphosphate